The Convair CV-240 is an American airliner produced by Convair from 1947 to 1954, initially as a possible replacement of the ubiquitous Douglas DC-3. Featuring a more modern design with cabin pressurization, the 240 series was able to make some inroads as a commercial airliner and also had a long development cycle which resulted in various civil and military variants. Although reduced in numbers through attrition, the "Convairliners" in various forms continue to fly into the 21st century.[1]

To meet the requirements of airlines for a pressurized airliner, Convair produced a revised design—the Model 240. This had a longer but thinner fuselage than the Model 110, accommodating 40 passengers in the first pressurized, twin-engined airliner.[4] The 240 first flew on March 16, 1947.[5]

The Model 240 was followed by the Model 340 that had a longer fuselage, longer-span wings and more powerful engines. The 340 first flew on October 5, 1951.[6] In 1954, in an attempt to compete with turboprop-powered airliners like the Vickers Viscount, Convair produced the Model 440 Metropolitan, with more streamlined cowlings, new engine exhausts, and better soundproofing for the cabin.[7] As the "Super 240" evolved into the CV-340 and CV-440, the limit of piston-engine performance was reached, and future development centered on conversion to turboprop power.[1]

A CV-240 was the first private aircraft used in a United States presidential campaign. In 1960, John F. Kennedy used a CV-240 named Caroline (after his daughter) during his campaign. This aircraft is now preserved in the National Air and Space Museum.

After aborted negotiations with TWA and Eastern for "Super 240" orders, the production of the 240 series was temporarily halted. In response to a United inquiry, Convair redesigned the Super 240, calling it the CV-340. United ordered 55, and more US orders came from Braniff, Continental, Delta, Northeast and National. Other orders came from abroad, and the CV-340 proved popular in South America. The CV-340 earned an enviable reputation for reliability and profitability, and was developed into the CV-440 Metropolitan, the final piston-engined variant of the "Convairliners."[1]

Turboprop-powered conversion fitted with Allison T38 engines. It became the first turboprop airliner to fly in the United States (on December 29, 1950), but problems with the engines resulted in development being terminated and the prototype being converted back to piston power.

Convair CV-300

A conversion from a Convair CV-240 with two R-2800 CB-17 engines and nacelles as used on the CV-340.[10] In 1977, a CV-300 was involved in an accident that killed three members and the manager of the rock group Lynyrd Skynyrd.[11]

Convair CV-340

Built for United Airlines and other operators including KLM, the CV-340 was a CV-240 lengthened to hold an additional four seats. The wingspan was extended for better performance at higher altitudes. The CV-340 replaced the DC-3 in United service. The airline flew 52 340s for 16 years without a fatality. KLM operated the type from early 1953 until mid-1963. Many CV-340 aircraft were converted to CV-440 standard.[12]

Convair CV-440 Metropolitan

CV-340 with improved soundproofing and an option for weather radar. Maximum weight rose to 49,700 lbs. An optional increase from 44 to 52 passengers was facilitated by the replacement of the carry-on luggage area with two more rows of seats, marked by the addition of an extra cabin window. This option was taken up by several airlines including Swissair, Lufthansa and SAS.[12]Finnair operated the type from 1953 until 1980 without a single accident.

Convair CV-540

Conversion from a Convair CV-340 aircraft with two Napier Eland turboprop engines in place of the piston engines. Six aircraft were converted by Napier for Allegheny Airlines.[13] Cost for the conversions was £160,000 per-aircraft. 12 built as new-builds by Canadair for RCAF as CC-109 in 1960 for £436,000 per-aircraft. First flight February 9, 1955.[14]

Conversion from a Convair 240 aircraft with Rolls-Royce Dart turboprop engines with four-blade propellers, in place of piston engines with three-blade propellers. CV-600 conversions were performed by Convair.[13] The CV-600 first flew with Central Airlines on 30 November 1965 and also served with Trans-Texas Airways (TTa) and successor Texas International Airlines for many years. The CV-600 aircraft that flew with Air Metro Airways was configured as a 40-passenger airliner. In 2012 the last Convair CV-600 (Rhoades Aviation) went out of service.[15]

Convair CV-640

Conversion from a Convair CV-340 or -440 with Rolls-Royce Dart turboprop engines with four-blade propellers, in place of piston engines with three-blade propellers. The conversions were performed by Convair.[13] In 2012, a total of seven Convair CV-640 aircraft remain in airline service, with Rhoades Aviation (one) and C&M Airways (six).[15]

Convair CV-5800

A stretched Convair CV-5800 of IFL Group

Conversion from former US Navy C-131F Samaritans by Kelowna Flightcraft Ltd. (KF Aerospace since 2015) in Canada. The CV-5800 is a C-131F Samaritan stretched by 16 ft 7 in (29,18 m)[16] with the Samaritan's original tail unit rather than the enlarged tail of the CV-580. These conversions also have a new freight door, digital avionics with EFIS and Allison 501-D22G engines in place of the original R-2800 engines. The prototype of this conversion first flew on February 11, 1992; the type certificate was issued on December 11, 1993.[17] A total of six aircraft were converted (construction numbers 276 to 279, 309, 343) and mostly used by Contract Air Cargo (later IFL Group); one aircraft was operated by Air Freight NZ.[18][19]

Conversion from CV-440, with Napier Eland turboprops in place of the piston engines. The conversions were performed in Canada by Canadair. In Royal Canadian Air Force and later in Canadian Armed Forces service they were known as the CC-109 Cosmopolitan. All were re-engined in 1966 with Allison 501-D13 engines.

Sun Valley Key Airlines - CV-440 (U.S. commuter air carrier previously known as Sun Valley Airlines that operated out of Salt Lake City, UT and Sun Valley, ID which then changed its name back to Key Airlines)